How do gun silencers work, and do they affect bullets?

How do gun silencers work, and do they affect bullets? --- Nathan, Milan, Tenn.

Marshall Brain Answered:

The basic idea behind a gun silencer is the same as a muffler for a car. In the case of a car engine, you have an exhaust valve opening and releasing a cylinder-full of high-pressure exhaust. In the case of a gun, the bullet uncorks the barrel as it exits the gun. Behind the bullet is high-pressure gas.

So a gun silencer's job is to take that high pressure gas and let it expand to lower the pressure. Then it wants to release that lower-pressure gas slowly rather than in a burst. Sort of like letting the air out of a balloon slowly rather than popping the balloon.

So a gun silencer lengthens the barrel of the gun and increases its diameter. This gives the gas behind the bullet room to expand. There are also baffles in the silencer to slow the gas down.

Silencers don't really affect the bullet's speed or accuracy because the silencer works on the gas behind the bullet rather than the bullet itself.